Zamora failed to make the grade at Tottenham after moving from Brighton, where he had scored 70 goals in 117 games, for £1.5million in 2003.
"He is a really good player. West Ham probably regret letting him go. Tottenham probably regret letting him go. He is really looking the part," said Redknapp.
"He shows well, holds the ball well and is full of confidence. He is looking a real top player. His all around game has improved, and everything has been clicking for him."
"I think he has a realistic shout (of playing for England)," said Redknapp. "Fabio was at the Juventus game and he must have been impressed with his performance. He is in the frame. He is bang in form.
"Anything can happen between now and then. One or two injuries. He is certainly not doing himself any harm."